Today we’re announcing schema.org, a new initiative from Google, Bing and Yahoo! to create and support a common set of schemas for structured data markup on web pages. Schema.org aims to be a one stop resource for webmasters looking to add markup to their pages to help search engines better understand their websites.

Example of a rich snippet: a search result enhanced by structured markup. In this case, the rich snippet contains a picture, reviews, and cook time for the recipe.

Adoption by the webmaster community has grown rapidly, and today we’re able to show rich snippets in search results more than ten times as often as when we started two years ago.

We want to continue making the open web richer and more useful. We know that it takes time and effort to add this markup to your pages, and adding markup is much harder if every search engine asks for data in a different way. That’s why we’ve come together with other search engines to support a common set of schemas, just as we came together to support a common standard for Sitemaps in 2006. With schema.org, site owners can improve how their sites appear in search results not only on Google, but on Bing, Yahoo! and potentially other search engines as well in the future.

Now let’s discuss some of the details of schema.org relevant to you as a webmaster:

1) Schema.org contains a lot of new markup types.
We’ve added more than 100 new types as well as ported over all of the existing rich snippets types. If you’ve looked at adding rich snippets markup before but none of the existing types were relevant for your site, it’s worth taking another look. Here are a few popular types:

Or, view a full list of all schema.org types. The new markup types may be used for future rich snippets formats as well as other types of improvements to help people find your content more easily when searching.

2) Schema.org uses microdata.
Historically, we’ve supported three different standards for structured data markup: microdata, microformats, and RDFa. We’ve decided to focus on just one format for schema.org to create a simpler story for webmasters and to improve consistency across search engines relying on the data. There are arguments to be made for preferring any of the existing standards, but we’ve found that microdata strikes a balance between the extensibility of RDFa and the simplicity of microformats, so this is the format that we’ve gone with.

To get an overview of microdata as well as the conventions followed by schema.org, take a look at the schema.org Getting Started guide.

3) We’ll continue to support our existing rich snippets markup formats.
If you’ve already done markup on your pages using microformats or RDFa, we’ll continue to support it. One caveat to watch out for: while it’s OK to use the new schema.org markup or continue to use existing microformats or RDFa markup, you should avoid mixing the formats together on the same web page, as this can confuse our parsers.

4) Test your markup using the rich snippets testing tool.
It’s very useful to test your web pages with markup to make sure we’re able to parse the data correctly. As with previous rich snippets markup formats, you should use the rich snippets testing tool for this purpose. Note that while the testing tool will show the marked up information that was parsed from the page, rich snippets previews are not yet shown for schema.org markup. We’ll be adding this functionality soon.

The schema.org website and the rich snippets testing tool are in English. However, Google shows rich snippets in search results globally, so there’s no need to wait to start marking up your pages.